Middle Ear Adenoma: A Challenging Diagnosis

Abstract

SUMMARY:Middle ear adenomas are rare benign tumors, which can easily be mistaken for other conditions radiologically. They derive from the middle ear mucosa. We report the case of a 48-year-old man with a history of decreased left-sided hearing and intermittent pulsatile tinnitus. High-resolution CT of the temporal bones revealed a well-defined left middle ear soft-tissue attenuation abutting the head of the malleus. Surgical excision revealed a middle ear adenoma. Since middle ear adenomas were first described by Hyams and Michaels 1 in 1976 and later that year by Derlacki and Barney, 2 they have become one of the unusual entities listed in the differential diagnosis of a middle ear mass. The clinical presentation and otoscopic and radiologic findings are nonspecific. Definitive diagnosis is based on histologic and immunohistochemical examination. 3 We report the case of a 48-year-old man with a history of left ear progressive symptoms, whose initial radiologic diagnosis favored glomus tympanicum versus cholesteatoma. Case ReportA 48-year-old man presented with a history of left ear progressive symptoms for 18 months (decreased hearing, intermittent pulsatile tinnitus, and a sensation of water in the ear canal, which did not clear with the nasal Valsalva maneuver). His otoscopic examination revealed a white smooth teardrop-shaped mass deep to the tympanic membrane, but the tympanic membrane and the external auditory canal were unremarkable. His audiogram showed a mild mixed hearing loss. On reviewing the middle ear through a binocular operating microscope, we found what appeared to be a large smooth fleshcolored mass, which arose to the level of the malleus. Insufflating the external auditory canal with air, we found that the mass appeared to blanch and return to its fleshy color once the pressure was stopped. Due to this finding and the absence of tympanic membrane perforation or chronic ear infection, the patient was referred for a temporal bone CT and octreotide scanning of the head and neck for a probable diagnosis of glomus tympanicum.Dedicated temporal CT of the left ear revealed a 1.0 ϫ 0.5 cm well-defined lobulated homogeneous soft-tissue-attenuation mass centered at the left cochlear promontory, which extended into the hypotympanum and filled the round window niche and the sinus tympani and also extended over the pyramidal eminence lying directly adjacent to the mastoid portion of the facial nerve. The lesion abutted the head of the malleus without vestibular, cochlear, or frank bony involvement. The octreotide scan demonstrated a left middle ear focus of intense radiotracer activity, most compatible with a neuroendocrine tumor; and on the basis of the findings of CT, the provisional diagnosis was a glomus tympanicum (Figs 1 and 2).The patient underwent surgery, during which the middle ear mass was resected by using a transmastoid and transcanal approach to the middle ear space, including facial recess dissection. The mass directly abutted not only the malleus but also the stapes, with no evidence of e...

Middle Ear Adenoma: A Rare Location for a Benign Tumor

“…The age of presentation is generally between the third and eighth decades, with a mean age of 45 years old and no sex preponderance [4]. Patients usually present with conductive hearing loss, ear fullness, tinnitus, facial muscles weakness or otalgia without a history of otological disease.…”

“…The MRI characteristics of the middle ear adenoma are low-to-intermediate intensity on T1weighted images, high intensity on T2-weighted images, and enhancement after administration of gadolinium [4].…”

“…Patients usually present with conductive hearing loss, ear fullness, tinnitus, facial muscles weakness or otalgia without a history of otological disease. These tumors are typically slow-growing and have an indolent onset which can delay the diagnosis [1][2][3][4][5][6][7][8][9][10]. The otoscopic examination shows a normal tympanic membrane with a grayish white or pink retro tympanic mass usually located in the promontory or hypotympanum, although it can be also found in the epytimpanyc area [2,4].…”

“…The clinical, otoscopic, audiologic and imaging findings are nonspecific. Definitive diagnosis is based on histological and immunohistochemical examination [1][2][3][4][5][6][7][8][9][10]. We report the case of a 48-year old man who was diagnosed and recently treated in our institution.…”

Opacification of the middle ear and mastoid: imaging findings and clues to differential diagnosis

“…MRI shows a T1-hypointense, T2-hyperintense lesion with contrast enhancement. 8,67 Focal tracer uptake in somatostatin-receptor PET/CT may be seen due to neuroendocrine differentiation. 72 The differential diagnosis includes tympanic soft-tissue changes, such as COM or cholesteatoma, and tumours such as a glomus tympanicum tumour or a facial nerve schwannoma as described in the above sections.…”